This invention refers to a device to clean air ducts, which consists of a header which is inserted In the duct to be cleaned, and which is connected by means of a supply hose, to a compressed air generator. The header is provided with a front part with an impact cushioning system, and a back part connected to the front and provided with compressed air outlets composed of flexible bands which move during the output of the compressed air, which significantly improves the effective cleaning of the inside surface of the duct, including recesses, corners and areas of difficult access.
As a background to the invention, different devices with the same cleaning purpose as this invention, can be mentioned. The European Patent E90850157 includes generating a major vacuum inside the duct to be cleaned, using an air current produced to move a cleaning element, such as a brush, inside the duct.
Patent E91905065 includes the use of a cleaning device connected, by means of a supply hose, to a compressed air source. This device consists of an annular groove through which the compressed air used to clean the duct, is projected, and at the same time producing reaction forces which are used to move the device inside the duct.
Patent E9197477 also includes a cleaning element connected by means of a duct, to a compressed air source. The element has one or more openings in the shape of nozzles, directed backwards. The cleaning elements have an annular groove-shaped nozzle, through which compressed air is discharged to clean the walls of the duct.
Similarly to the previous two, Patent WO 9324246 consists of a duct which connects a compressed air source to a spherical body provided with outlets for the compressed air, directed towards the back, so that the duct is cleaned at the same time as the body advances.
These devices include, therefore, a cleaning element which is connected by a supply hose, to a compressed air source. This cleaning element has compressed air outlets, which simultaneously clean the duct and move the element forward.
These devices have different problems; when the cleaning element is operating, movements are abrupt and uncontrolled, owing to the reaction forces produced by the outlet of compressed air, causing the element to continuously knock against the walls of the duct being cleaned and leading to damage. Also, when these cleaning elements move forward in an uncontrolled fashion, it is possible that corners and recesses where compressed air is not sufficient, may not be cleaned properly. Finally, the diameter, the section or the upward downward or zigzag lay-out of the duct are features which, separately or together prevent these current methods of cleaning from being used, meaning that it is necessary to have several different types of methods or leave lengths of duct uncleaned.
The device of this Invention consists of a header which is inserted inside the duct to be cleaned, and connected by means of a supply hose to a compressed air generator. This header consists of two parts, a front part and a back part, which are held together by means of a thread. Many flexible bands are connected to the back part, through which all or part of the compressed air emerges.
The front part consists of a low density soft body and hard body, with a diameter greater than all the components of the header, in order to cushion possible knocks of the header against the walls of the duct, preventing damage both to these walls and to the header.
The thread which connects the front to the back part can be a screw type with nut, in which case, the soft body and the hard body are bore-holed, so that the screw passes through the hole to the rear part, which holds the socket of the nut. The screw and ring are loose parts, or they can be placed in the back of the front part and capped in a cavity coinciding with the front surface of the back part.
The coupling of the two main parts, up until now called the front and the back, is such that the distance between them can be adjusted, so that if they are completely joined, all the compressed air has to go out through the bands, but if a distance is left, adjusted on unscrewing the front part if it can be unscrewed, or through the planned manufacture of the hard body of the front part when both main parts are joined by screw and nut, the compressed air will also go out through this circular groove. The curtain of air formed when the compressed air goes out through the circular groove, means that the bands moving at random, will never be in front of the header as they will not be able to cross through the curtain, and in some types of cleaning, this is an extra advantage.
The compressed air enters the unit of the two parts through the back part, which has a tubular tab at the back to connect the hose connected to the compressed air generator. The inside hole of the tubular tab is prolonged to the front surface of this back part, and from there it is distributed to be ejected through the bands or through the groove left between the two main parts.
This back part also has many holes in the front, which extend to the back surface of the back part. Soft and flexible bands are attached to these holes, which are therefore directed towards the back of the header.
The reaction force caused by the discharge of compressed air through the bands, makes them move at random, which together with the fact that the length of these bands is adjusted to the diameter of the duct, causes them to lash on the layers of dirt deposited on the walls of the duct and to ensure deep cleansing of the duct, which up until now was impossible, as when the bands lash against the walls, they peel off the dirt which is compacted against the wall and which cannot be cleaned with a jet of compressed air alone. As the bands are flexible and soft, they do not cause damage to the duct when they lash against the walls.